1. Field of the Invention
The present invention relates to a wrist watch containing tag which uses radio frequency identification.
2. Description of the Related Art
Conventionally, plates such as ID charts and name cards are used in visually identifying persons and objects, but only a very limited amount of information can be displayed on such plates. For this reason, a tag has recently been developed which has an identification function electronically appended thereto by using RFID (radio frequency identification). The tag for identification comprises an IC chip and an antenna, electrically connected to the IC chip, and is attached on the plate, enabling information printed on the surface of the plate to be identified by sight, and making it possible to store a wide variety of information on the plate. For example, incoming/outgoing persons and objects can be controlled by attaching the tagged plates to them, and automatically reading the information stored in the IC chips.
Recently, this type of tag for identification is used as an identification device at entrance gates of ski lifts and rides in amusement parks, and as a ticket or commuter pass for trains and buses. By using this type of tag for identification in entrance gates and transportation systems, passengers attempting to board a ski lift, an amusement park ride, and a bus or train, can identify themselves as legitimate passengers by a simple operation of holding their tags near to an identification unit, provided at the gate.
The passengers who board the lifts, rides, buses, and the like, are usually wearing wrist watches. For this reason, there have been attempts to install tags for identification in the wrist watches. If this could be achieved, there would be no need to carry the tag for identification separately from the wrist watch, and the tag for identification could be fitted to a passenger""s wrist without any sense of discomfort, potentially increasing its conventional field of use.
FIG. 19 shows a conventional wrist watch having a watch case 2, comprising a ring-shaped frame 2a, a glass lid 2b which seals the top side of the ring-shaped frame 2a, and a bottom lid 2c which seals the bottom side of the ring-shaped frame 2a, a drive section 3 which is accommodated inside the watch case 2, and a display section 4 which displays the time and is driven by the drive section, accommodated in the watch case 2. The display section 4 and the drive section 3 are provided in that order inside the ring-shaped frame 2a, the top side of which is sealed by the glass lid 2b, and lastly the bottom side of the ring-shaped frame 2a is sealed by the bottom lid 2c, to complete the structure of the wrist watch 1. Therefore, to provide a tag for identification in the conventional wrist watch 1, a coil is wound round the comparatively spacious area around the drive section 3 (i.e. along the inner face of the ring-shaped frame 2a) so as to surround the drive section 3, and this coil is used as an antenna for an RFID tag. The magnetic axis of the antenna comprising the coil is perpendicular to the watchface, which has the largest area, and consequently increases the sensitivity of the RFID tag when utilizing the wrist watch as an identification device, and lengthens its operational distance.
However, the ring-shaped frame of conventional wrist watches is made of an electrically conductive metal, in order to ensure durability and obtain a sense of luxury. As a result, when a coil is wound along the frame member so as to accommodate an antenna inside the wrist watch, an inductive current flows to the frame member when the antenna receives radio waves, canceling the electrical waves from the outside. In addition, when an electrical current has flowed along the coil forming the antenna, current may also flow into the metallic frame member, greatly deteriorating the sensitivity of the antenna and greatly shortening the operational distance of the RFID tag. One conceivable method of eliminating these problems is to use a frame member of nonconductive resin in the watch case of the wrist watch, but a frame member comprising resin does not produce any sense of luxury, and has poor durability. For the same reasons as the frame member, the bottom lid provided on the bottom side of the frame member is preferably made of metal, but a metal bottom lid fails to achieve sufficient antenna sensitivity.
It is a first object of this invention to provide a wrist watch containing tag which contains an RFID tag having high antenna sensitivity, and is durable and expresses a sense of luxury.
The wrist watch containing tag of this invention comprises a watch case having a ring-shaped frame, a glass lid which seals a top side of the ring-shaped frame, and a bottom lid which seals a bottom side of the ring-shaped frame; a drive section which is accommodated inside the watch case, a display section for displaying time which is accommodated inside the watch case and is driven by the drive section, and an RFID tag which is accommodated inside the watch case and comprises an antenna and an IC chip. The antenna comprises a wound coil which runs along the inner face of the ring-shaped frame so as to surround the drive section. At least one of the ring-shaped frame and the bottom lid comprises a metal material, and in addition, a slit for preventing the generation of inductive current is provided in at least one of the ring-shaped frame and the bottom lid which comprise the metal material.
This constitution is characterized in that the ring-shaped frame comprises a metal material, the bottom lid comprises an electrical insulating material, a slit is provided in at least one position of the ring-shaped frame by cutting across the ring-shaped frame, and the antenna has a coil which is wound along the inner face of the ring-shaped frame so as to surround the drive section.
When the wrist watch containing tag is worn on the wrist, the metal material of the ring-shaped frame around the glass lid expresses the original sense of luxury of the wrist watch. Since the bottom lid is comprised of an electrically insulated material, it does not obstruct the radio waves which are to be received by the antenna of the RFID tag accommodated inside the watch case.
Further, since the coil of the antenna is wound along the inner face of the ring-shaped frame so as to surround the drive section, the magnetic axis of the antenna becomes perpendicular to the watchface, increasing the sensitivity of the RFID tag and achieving a comparatively long operation distance. In this case, since the ring-shaped frame has at least one slit, no inductive current flows to the ring-shaped frame member, thereby ensuring that the sensitivity of the antenna does not deteriorate.
In the wrist watch containing tag of this invention, the slit is filled with a nonconductive resin, affixing together opposing cutaway planes which form the slit.
Since the opposing cutaway planes of the slit, which is cut across the ring-shaped frame, are affixed together, dust, water droplets, and such like, can be prevented from entering the slit, and the strength of the ring-shaped frame is prevented from deteriorating due to the provision of the slit. The watch case comprising the ring-shaped frame maintains its durability.
In the wrist watch containing tag of this invention, the opposing cutaway planes which form the slit comprise a plurality of continuous cutaway planes.
This increases the adhesive strength of the nonconductive resin, which is filled in the slit comprising the plurality of cutaway planes, and increases the strength of the ring-shaped frame.
Further, according to the wrist watch containing tag of this invention, an indent is provided in the top side and/or the bottom side of the ring-shaped frame, the slit is provided across the indent, and a clip member comprising the same material as the ring-shaped frame is affixed in the indent with the nonconductive resin therebetween.
Since the nonconductive resin is provided between the clip member and the indent, no inductive current flows to the frame member. By affixing a clip member of the same material as the ring-shaped frame into the indent, the clip member is able to cover the slit, concealing the slit from the outside and consequently improving the external appearance of the wrist watch.
Further, according to the wrist watch containing tag of this invention, the antenna comprises a magnetic core member along the inner face of the ring-shaped frame so as to surround the drive section, the coil being wound around the outer periphery of the magnetic core member.
In this wrist watch containing tag, the antenna comprises the magnetic core member, and therefore, the receiving sensitivity of the antenna can be increased.
Further, according to the wrist watch containing tag of this invention, the magnetic core member comprises a bobbin-like shape having a winding frame for coil, and is comprised of a compound material of magnetic powder or flakes and plastic.
The magnetic core member is formed by injection-molding or compression-molding of a compound material.
By forming the compound material in a bobbin-like shape, it becomes easier to wind the coil, and the magnetic core member can be obtained in any given shape, making it possible to achieve a comparatively inexpensive antenna.
Further, according to the wrist watch containing tag of this invention, the magnetic core member is formed by winding a magnetic painted film, made by applying and drying a paint or ink comprising powder or flakes of a magnetic material.
Therefore, a magnetic core member can be obtained which has a thickness of less than 0.8 mm, at which injection-molding becomes difficult. Moreover, even when the gap between the inner face of the ring-shaped frame and the outer face of the drive section is narrow, the RFID tag having the magnetic core member can be accommodated in the gap.
Furthermore, wrist watch containing tag according to this invention comprises a watch case having a ring-shaped frame, a glass lid which seals a top side of the ring-shaped frame, and a bottom lid which seals a bottom side of the ring-shaped frame; a drive section which is accommodated inside the watch case; a display section for displaying time which is accommodated inside the watch case and is driven by the drive section, and an RFID tag which is accommodated inside the watch case and comprises an antenna and an IC chip.
This constitution is characterized in that the antenna has a coil which is wound along the inner face of the ring-shaped frame so as to surround the drive section, the bottom lid comprises a metal main lid, or a nonmetal main lid and a metal supplementary lid, which is affixed so as to cover the nonmetal main lid; and one, two, or more, slits are provided in at least one end of the metal main lid and the metal supplementary lid, the slits extending to the outer edge thereof.
Since the metal main lid and the metal supplementary lid are comprised of a metal material, the original sense of luxury of the wrist watch can be expressed. In addition, since one, two, or more, slits extend to the outer edges of the metal main lid and the metal supplementary lid, a ring-shaped inductive current can be prevented from flowing around the metal main lid and the metal supplementary lid at the time of receiving waves, preventing the radio waves from being cancelled by the inductive current and preventing the sensitivity of the antenna from deteriorating.
Further, since the coil of the antenna is wound along the inner face of the ring-shaped frame so as to surround the drive section, the magnetic axis becomes perpendicular to the clock case, increasing the sensitivity of the RFID tag and achieving a comparatively long operating distance.
In the wrist watch containing tag of this invention, the slit(s) is/are filled with a nonconductive resin, affixing together the opposing cutaway planes which form the slit(s).
Therefore, dust, water droplets, and such like, can be prevented from entering the slit(s), and the strength of the ring-shaped frame is prevented from deteriorating due to the provision of the slit(s) For this reason, the watch case maintains its durability.
In the wrist watch containing tag of this invention, two or more slits radiate from the center of the metal main lid and the metal supplementary lid.
This enables the slits to be provided uniformly in the metal main lid and the metal supplementary lid, improving the external appearance.
Further, according to the wrist watch containing tag of this invention, the antenna comprises a magnetic core member, provided along the inner face of the ring-shaped frame so as to surround the drive section, and the coil is wound around the outer periphery of the magnetic core member.
Since the antenna comprises the magnetic core member, the receiving sensitivity of the antenna itself can be increased.
Further, according to the wrist watch containing tag of this invention, the magnetic core member comprises a bobbin-like shape, which has a winding frame for coil and is comprised of a compound material of magnetic powder or flakes and plastic.
The magnetic core member of this wrist watch containing tag is formed by injection-molding or compression-molding of a compound material.
The metal main lid and the metal supplementary lid can be made together in a single piece by injection-molding or compression-molding of the compound material
By forming the compound material in a bobbin-like shape, it becomes easier to wind the coil, and the magnetic core member can be obtained in any given shape, making it possible to achieve a comparatively inexpensive antenna. Further, the magnetic core member and the metal supplementary lid can be made together in a single piece, simplifying the manufacturing process, and making it possible to obtain a comparatively inexpensive wrist watch containing tag.
According to the wrist watch containing tag of this invention, the magnetic core member is formed by winding a magnetic painted film, made by applying and drying a paint or ink comprising powder or flakes of a magnetic material, into a ring-shape.
Therefore, a magnetic core member can be obtained which has a thickness of less than 0.8 mm, at which injection-molding becomes difficult. Moreover, even when the gap between the inner face of the ring-shaped frame and the outer face of the drive section is narrow, the RFID tag having the magnetic core member can be accommodated in the gap.